Laurent, it is a nice puzzle with a lot of tactical elements involved from forks and pins to the zugzwang. thanks for sharing.

Here is the full solution :

Hello Solomon,

Congratulations. You've even added a defence I hadn't thought of (2...Bc8).

There are three interesting patterns in this study :

- the Ne4 idea : protecting the white pawns from behind by preventing the black king from entering their square

- the f and h pawns that the black bishop can't stop (f7, Bxf7, h7)

- and of course the Knight forks, which are possible because all three pieces (King, Knight and Bishop) are on squares of the same color and the king is adjacent to the Knight.

Correction on my wrong solution below. Kd1 Bc8 gives black the draw unfortunately. Kd2 is the correct first move so after Bc8, Nd2 Bxd2 and advance our f-pawn and h-pawn. if Kd1, Bc8 Nd2 will not work b/c after Bxd2, black threatens Bg4+ and takes the h-pawn. Kd2 avoids the check.

i'm sorry i didn't read the thread below. i think the solution rests on white's king being able to catch a1 and the amazing coincidence of the N threatening to fork the B and king if the B decides to move anywhere. beautiful knight.

@Laurent I know that it is cheating, but you asked the question and therefore I assume that Kd1 isn't as good :) I am yet to find out why, but as I said, the king is on a light square now, where it might possibly receive check from the bishop.

5-7 minutes after writing the above I found it! I firstly checked 1. Kd1 Ke5 2. Ne4 but Kc1 is soonly played and so the outcome is the same. After 2. Be2+ Kxe2 it's an easy game :)

So the problem must be with 1. Kd1 Bc8. I played the exact same line ( 1. Kd1 Bc8 2. Nd7 Bxd7 3. f6 but now Bg4+ and white is doomed to a draw!

I hope and think I have found the right to solution to this great problem, thank you for sharing it with me!

@Joey, fantastic job finding all of this. I hope you enjoyed the process

Now, one very last question to wrap it all : you suggested 1.Kd1 as a possible 1st move. Do you still think it's as good as 1.Kd2 ?

Just a few minutes after posting that last long, long post, I think I've found the solution to 1. Kd2 Bc8 as well! First of all, it is very important for white to not allow black to grab the f-pawn. That can be done on two manners: moving the f-pawn or protecting it. It's clear that protecting it can't be done but it can be moved! after 2. Nd7 Bxd7 3. f6 the pawns can promote! 3. ... Be6 4. h6 Bg8 5. h7 promotes one of the pawns and wins the game! I don't see any other good response to 2. Nd7 so I guess that's it. Now I'm pretty sure I was right on 1. Kd2 after all :)

@hicetnunc thank you for throwing me those problems, they really made me think. I must admit I used the analysis board, so I didn't train much calculation. For your first question, Kc1 seems obvious. 1. Kd2 Ke5 2. Ne4 Kxf5 3. Kc3 a3! 4. Kb3 Kxe4! and there's two variations. 5. h6 Bc4+ either stops the h-pawn or allows black to promote the a-pawn first or 5. Kxa3 which also leads to Bc4 again stopping the h-pawn and therefore drawing. 

Kc1 however allows the king to go to b1 after a3, thus being able to stop that a-pawn. It is, however, important for the king not to go to a2, for that again leads to Bc4 with check. So after 3. Kb1 a3+ or 3. ... a4 4. Ka1! is the only response. After which black must move either a3 in the first variation or a2 in the second.

So far so good. But if the king can't take on a2, what is there to do? c3 can't move, for it allows Bd4. h6 also can't move for that allows Kg6. Also obviously the knight cant move, for it will take away any threat of the fork and Kg5 is allowed, grabbing the h-pawn.

Thankfully, the king can still move to b2! I've spend like 20 minutes on the problem after a2+, but I think I have the solution now. 4. Kb1 a2+ 5. Ka1 a4 6. Kb2! and now 6. ... a1=Q 7. Kxa1 and the other pawn is forced to proceed to the king while the king goes 7. ... a3 Kb1 8. a2+ Ka1!. Now either black's king or bishop must move which leads to promotion of the h-pawn or loss of the bishop through a pin. (4. ... a4 leads to the same position after a different move order, but I think you understand that.

Now I'll look at your idea of 1. Kd2 Bc8 further but I haven't found anything to that yet. I do hope my efforts on 1. Kd2 actually pay off and that I find a solution for 1. ... Bc8. I promise you I'll come to that later!

@PureJay : congratulations on spotting all those nice ideas (I'm not right in any way more than you here, just have the advantage of knowing the solution )

After 1.Kd2 Ke5 2.Ne4 Kxf5 would you rather go Kc1 or Kc3 ? (you may want to try and solve it in your head, as it helps develop your calculation/visualization skills).

If you have enough energy, you might also want to have a look at another black's defence, namely 1.Kd2 Bc8!?

@hicetnunc

I looked at it for quite some time now and I think I was on the right track.
You gave 1. Kd2 Ke5 2. Ne4 Kxf5 and doubted that the h-pawn could promote, in which you were right and I was wrong.

Now here is the trick: the bishop can't move! any move by the bishop leads to a fork with the knight with the king. Also the king can't move for that would enable the pawn to promote or again allow a fork after 3. Ke6 Nc5+

So the only option for black is to move the a-pawns, which can be easily grabbed by white's dear king, and afterwards the king could help any of the two remaining pawns to promote and win the game.

Is there anything I overlooked? I hope not, for I looked at it for quite a long time :) 

@Nimzo : I think the interest with these positions is to look for the solution before seeing it. In puzzle mode, there is a big temptation to 'just try some move and then look at the solution'.

2 or 3 tries with some hints in between may be better for training purposes, but that's just my opinion.

@erratadei : 4...Kd5 is illegal, but Black has 4...Qf1+ at his disposal.

@MCRex : you have to look at the forcing 1.Ne4 a3 first to assess the merits of your idea.

Ne4 anyone? if Kxe4 then h6 a3 h7 a2 h8=Q and black can't queen as white's queen is guarding the square. This does not work in the original position because white's knight is on the long diagonal. The threat of Ne4 is Nd2 then Nb3, stopping any queening activity and checking depending on the variation

EDIT:

Nb3 would not be *stopping* queening activity, but it would cost black some very valuable tempi in dislodging the knight-in all variations (I believe, but I am no expert) black is losing that one extremely important tempo

this is what comes into mind, but not a nice outcome and i guess there is something better

1. h6 a3 2. h7 a2 3. Nh5 a1=Q+ 4. Kf2 Kd5 5. f6

Posting it as a puzzle instead of a diagram would elicit more interest IMHO - since you're going to the trouble of posting it in the first place.

I tried pawn c3+ but that is also a draw.

hmm, no clue :)

@PureJay : 1.Kd1 Bc8 ; 1.Kd2 Ke5 2.Ne4 Kxf5 and how do you promote the h pawn ?

@lisle : yes, but black promotes with check on a1...

this is an easy one... it's pawn to h6... I can't see how black stops the pawn from queening

Haven't looked at it much, but at first sight I guess the king should go to a1 immediately. So via d2 or d1, don't really see any difference, maybe better to stay on the dark squares. After Ke5 white plays Ne4 to take away the g5-square for the king and I guess the h-pawn could easily promote soon